We may have found other answers which could help you.
Click here for Problem Working Hot WaterFerolli Optimax HE 31C expansion vessel change?
How turn off heating in Ferolli Optimax 31c?
F40 fault?
i have a ferroli combi boiler i have 1/2 the radiators working and 1/2 not ?
Ferroli DOMIcompact F 30 D?
Ferroli Optimax HE31c a26 problem?